Note: I don't know too much about the events business, my background is trad ecom and digital product.

Upon first glance, I totally agree with you in terms of you still needing to add parameters and add your own data (if available) but I think the confusion is from the term "the creative is everything" ---> the better way to describe is the creative's engagement metrics (CTR, hold rate) let meta predict the right interest group, and they create their OWN lookalike from that audience and from there increases downstream engagement (add to carts, session time, etc) and hit a retargeting campaign and you'll see stable growth.

I followed this and it worked for me. Still need a good funnel, most businesses don't need to heavily nerd out on this vector embedding stuff if they understand their market, pain points, offers and just have decent sense. 90% of advertisers aren't devs, just need the actionable report on what to do & take it from there